The present invention relates generally to agricultural machinery and, more particularly, to improvements to balers for harvested crops.
A self-driven or pulled baler for producing pressed bales of harvested crops has a crank-driven reciprocating baling ram, located in the pressing channel, a crop feeding channel leading into the pressing channel, and a crop rake consisting of a rake lever and a plurality of rakes in the pressing channel. The crop rake is driven by a crank drive. The motion track of the feed rakes can be changed for crop feeding or loading strokes. The rake levers are pivotally mounted at one end on crank pins and their opposite ends are connected with an end of the joint rod. The joint rod's other end is mounted on a movable bearing. The self-driven or pulled baler also has a pick-up device for baled crops, as well as a drive and control devices for the operation of the baling ram.
A baler of the aforementioned type is shown and described in German Patent No. 36 38 792. In this baler, the crank drive for the piston ram is forcibly connected with the crank drive of the feed rakes. After two feed strokes, which transfer the harvested crops into the feeding channel, the feed rakes perform a single loading stroke, transferring the harvested crops from the feeding channel into the baling channel. This motion of the feed rakes is cyclically repeated, so that even if a very small amount of crops is in the feeding channel, every third rake stroke becomes indispensably a loading stroke. As a result, with each loading stroke, different amounts of pre-compressed crops are fed into the actual bale chamber. The resulting disadvantage can be seen in the final product, especially in cases of fluctuating amounts of picked-up crops, which results in non-uniform, irregularly compressed or formed bales.
To avoid irregularly formed bales it is known from German Patent Publication No. 27 59 533 to install a feeding drum, more specifically a rotational feeder, in the balers' feeding channel. The feeding drum is equipped with controlled fingers which feed the crops against a pressure sensor in the feeding channel. In addition to the feeding drum, feed rakes are installed to aid in the uniform shaping and forming of the bales. Once the pre-set pressure in the pressure sensor is reached, the feed rakes enter through slits in the feeding channel and feed the pre-compressed crops into the actual baling chamber. The arrangement of the feeding drum operating with controlled fingers and the additional feed rakes, which are necessary for the loading stroke, has very high construction costs. Also, in severe circumstances, the feeding drum is incapable of completely filling the feeding channel.
In addition, German Patent Publication No. 195 31 240 shows a class-type piston ram with a rotational feeder whose feeding mechanisms are movable along a feeding curve. According to the description, the invention feeds uniformly dense amounts of crop portions into the pressing channel. The uniformity of the feeding portions should be accomplished by manipulating the feeding mechanism's curve track, resulting in a variation of volume and density of the partial amounts of subset portions. However, this solution is unsuitable to create uniformly dense feeding portions for small crop amounts, because if a required minimum volume is underfed, the fill volume of a feeding portion will not completely fill the pressing channel. Additionally, the rotational feeders have much higher manufacturing costs and also have the disadvantage that the rollers of the gate shift guide for the controlled fingers are subject to high wear.
It is desirable to provide a baler that overcomes one or more of the deficiencies noted above.
An objective of the present invention is to provide a baler having lever arm-controlled feed rakes as the exclusive feeding mechanism, where uniformly pre-pressing the harvested crops and forming uniformly sized and shaped bales can be accomplished, even with small amounts of harvested crops, without the assistance of additional feeding devices in the feeding channel.